I have a 78 Ford 1600 as well. I can't answer your question, but thought it might be nice to exchange ideas since very few of us have these machines in which parts are very hard to come by. When I drained my fuel injection pump, a clear liquid came out. Not oil, as I had expected. More like Kerosene?? Not sure. The op's manual says use engine oil. Can someone verify this for me?
Does anyone have the description page referencing the numbers on the diagram.?Here's a break-out I found in my files of the Fuel Injection Pump